Modify UUID sentinel to support keystone-like UUIDs

Keystone User IDs and Project IDs are used in unit tests, but
_UUIDSentinels() class doesn't generate UUIDs without hyphens.

This patch makes backward compatible modifications to
_UUIDSentinels() class and introduces keystoneidsentinel global
that could be used in the same way as existing uuidsentinel.

Original "UUID sentinel" change: I214ff21b461fa1ca4b83476e1d0a763efe986217

Related-Bug: #1746747
Change-Id: Idb3e893cc03d64ad0522b5e4cedfa30c4f4a2a2f

oslo_utils/fixture.py

@@ -55,7 +55,8 @@ class TimeFixture(fixtures.Fixture):
 
 
 class _UUIDSentinels(object):
-    """Registry of dynamically created, named, random UUID strings.
+    """Registry of dynamically created, named, random UUID strings in regular
+    (with hyphens) and similar to some keystone IDs (without hyphens) formats.
 
     An instance of this class will dynamically generate attributes as they are
     referenced, associating a random UUID string with each. Thereafter,
@@ -65,6 +66,7 @@ class _UUIDSentinels(object):
     Usage::
 
         from oslo_utils.fixture import uuidsentinel as uuids
+        from oslo_utils.fixture import keystoneidsentinel as keystids
         ...
         foo = uuids.foo
         do_a_thing(foo)
@@ -72,17 +74,22 @@ class _UUIDSentinels(object):
         assert foo == uuids.foo
         # But a different one will be different
         assert foo != uuids.bar
+        # Same approach is valid for keystoneidsentinel:
+        data = create_some_data_structure(keystids.bar, var1, var2, var3)
+        assert extract_bar(data) == keystids.bar
     """
-    def __init__(self):
+    def __init__(self, is_dashed=True):
         self._sentinels = {}
         self._lock = threading.Lock()
+        self.is_dashed = is_dashed
 
     def __getattr__(self, name):
         if name.startswith('_'):
             raise AttributeError('Sentinels must not start with _')
         with self._lock:
             if name not in self._sentinels:
-                self._sentinels[name] = uuidutils.generate_uuid()
+                self._sentinels[name] = uuidutils.generate_uuid(
+                    dashed=self.is_dashed)
         return self._sentinels[name]
 
 
@@ -90,3 +97,4 @@ class _UUIDSentinels(object):
 # same process (including across multiple modules) will result in the same
 # values
 uuidsentinel = _UUIDSentinels()
+keystoneidsentinel = _UUIDSentinels(is_dashed=False)

oslo_utils/tests/test_fixture.py

@@ -19,6 +19,7 @@ import datetime
 from oslotest import base as test_base
 
 from oslo_utils import fixture
+from oslo_utils.fixture import keystoneidsentinel as keystids
 from oslo_utils.fixture import uuidsentinel as uuids
 from oslo_utils import timeutils
 from oslo_utils import uuidutils
@@ -71,13 +72,20 @@ class UUIDSentinelsTest(test_base.BaseTestCase):
         uuid1 = uuids.foobar
         uuid2 = uuids.barfoo
         self.assertNotEqual(uuid1, uuid2)
+        keystid1 = keystids.foobar
+        keystid2 = keystids.barfoo
+        self.assertNotEqual(keystid1, keystid2)
 
     def test_returns_uuid(self):
         self.assertTrue(uuidutils.is_uuid_like(uuids.foo))
+        self.assertTrue(uuidutils.is_uuid_like(keystids.foo))
 
     def test_returns_string(self):
         self.assertIsInstance(uuids.foo, str)
+        self.assertIsInstance(keystids.foo, str)
 
     def test_with_underline_prefix(self):
         ex = self.assertRaises(AttributeError, getattr, uuids, '_foo')
         self.assertIn("Sentinels must not start with _", str(ex))
+        ex = self.assertRaises(AttributeError, getattr, keystids, '_foo')
+        self.assertIn("Sentinels must not start with _", str(ex))

releasenotes/notes/introduce-keystoneidsentinel-16bf3e7f2ae7e9f3.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    keystoneidsentinel singleton was introduced to generate
+    random keystone-like UUIDs. New sentinel could be used in the same
+    way as existing uuidsentinel.